Welcome to the twenty-second edition of FOI Clinical. Each week, we'll send you a briefing on outbreak news. When something urgent breaks, you'll get an alert the same day.
In this edition
Tularemia – Measles – Brucellosis: California – Mumps: Maryland – Malaria: Maryland – Legionnaires: NYC – Grand Canyon unknown – Powassan: New England – Plague rule out – Ebola – Marburg – Measles in the Americas
National interest
Tularemia
Peak season is underway; 78% of annual U.S. tularemia cases occur May–September. Reports this year are lower than during the same period last year, with 38 cases reported vs. 95 prior year (0.4x). The below-baseline count may partly reflect a January 2026 case definition revision (CSTE 25-ID-09) that tightened probable case criteria.
The 2025 MMWR published the first tularemia treatment update since 2001. Key changes:
- Non-severe: ciprofloxacin 750 mg PO q12h ×10d or levofloxacin 750 mg q24h ×10d (first-line)
- Severe/hospitalized: gentamicin 6 mg/kg IV/IM q24h ×10d (preferred when diagnosis delayed >2 weeks)
- Post-exposure prophylaxis: shortened from 14 to 7 days (cipro or levofloxacin)
- Streptomycin demoted to third-tier; β-lactams and macrolides are ineffective
- Scalp examination is essential. Scalp ulcers are easily missed in febrile patients with cervical adenopathy and outdoor exposure
Francisella tularensis is a Tier 1 Select Agent with an infectious dose of <10 organisms by inhalation.
Measles
CDC updated to 2,170 confirmed cases on July 2, up 36 from last week, across 41 jurisdictions. The 2026 year to date total is now 119 cases short of matching all of 2025 (2,289 full-year) with five months remaining; the PAHO elimination-status review convenes in November.
State updates:
- Utah: 704 total (507 in 2026), up 5 since last week.
- Virginia: 167 cases. Up 26 since the June 30 count. Buckingham and Cumberland County outbreak ongoing. The June 17 Dulles Airport exposure monitoring window closed July 8 with no confirmed secondary cases.
- Texas: 182 cases. Unchanged since June 24, centered in Hudspeth County federal detention facilities.
Regional interest
Brucellosis: California
California accounts for 16 of 37 national brucellosis cases year to date (43%), well above its historical ~21% share. LA County DPH announced a South Los Angeles County cluster of Brucella melitensis infections on May 23, linked to unpasteurized cheese imported from Mexico. No brand has been publicly named and no recall has been issued.
B. melitensis, responsible for 57% of CDC-tested U.S. isolates, is almost exclusively associated with small ruminant dairy (goat, sheep). Mexico accounts for 58% of travel-linked U.S. brucellosis cases. Clinicians in Southern California should ask about raw dairy consumption in patients presenting with undulant fever, arthralgia, or unexplained hepatitis.
Mumps: Maryland
Maryland accounts for 49 of 122 national mumps cases to date (40.2%), concentrated in Baltimore City and surrounding counties (Anne Arundel, Baltimore County, Carroll, Harford, Howard, Queen Anne's). The cluster has been active since February 2026, when the Maryland Department of Health (MDH) announced 26 cases, six times the full-year 2025 total, and has grown steadily since with no common exposure identified.